Time element electroresponsive device



Sept. 2, 1941, T. 1 H. BUTTERFIELD TIME ELEMENT ELECTRORESPONSIVE DEVICE Fiied Aug. 1, 1940 Inventor:

Trevor LLI-1v BLJtteF'ie I d Patented Sept. 2, 1941 TIME ELEMENT ELECTRORESPONSIVE DEVICE Trevor Lunsden Herbert Butterfield, Sale, England, assignor to General Electric Company, a corporation of New York Application August 1, 1940, Serial No. 349,329 In Great Britain August 10, 1939 12 Claims.

My invention relates to improvements in time element electroresponsive devices and particularly timing relays in which contacts of the relay are operated after the expiration of a predetermined time period from the initiation of the relay into operation. My invention provides such a timing relay which is eminently adapted for use in controlling the duration of current flow in spot welding equipments. It is to be understood, however, that my invention is in no way limited in this respect and that relays embodying my invention may be employed for other applications in which a timed operation is required.

One object of my invention is to provide a time element electroresponsive device which has a wide range in operating times. A second object of my invention is to provide a time element electroresponsive device whose operating times are accurate and dependable throughout its operating range. A third object of my invention is to provide an improved time element electroresponsive device in which friction losses are so minimized as to exert the least effect on the timing operation. A fourth object of my invention is to provide a time element electroresponsive device in which the return movement of the timed operating member is substantially free of appreciable time delay. These and other objects of my invention will appear in more detail hereinafter.

In accordance with my invention, the time element electroresponsive device comprises a constant speed motor which is arranged to rotate continuously, and a contact actuating element which upon initiation into operation is coupled with said motor so as to be moved with the latter during a predetermined angular movement of the motor before actuating the contacts of the device, means being provided whereby the mechanical connection between the contact actuat` ing elemeni-l and the motor is interrupted preparatory to the next timing operation of the device.

The device is preferably arranged so that the contact actuating element is released from the motor when the latter has completed a predetermined angular movement, namely, at the end of a predetermined time period, and so that theY contacts are actuated by movement of the contact actuating element after the latter has been so released from the motor.

More specifically, my invention provides a timing relay in which in response tothe application actuating element is associated with a synchronous electric motor and means are provided which upon application of an operating force to said element in a direction to cause actuation of said contacts, causes said element to be coupled mechanically with said motor during a predetermined angular movement of the latter whereby the movement of the contact actuating element b-y the operating force thereon is restrained by the synchronous motor for a predetermined time period (after the initial application of said operating force) prior to the actuation of said contacts by said element. The synchronous electric motor may be replaced if desired by other forms of motor which will rotate at constant speed and are adapted to apply to the contact actuating element a retarding force suitable for limiting the speed of the latter, when under the iniuence of the operating force, to the speed corresponding with that of the motor. The means for coupling the contact actuating element with the motor are preferably arranged so that at K the end of the predetermined time period the contact actuating element is disengaged from the motor whereby the latter will continue to rotate whilst the further movement of the contact actuating element under the action of said operating force may be arrested due to engagement of the relay contacts.

According to a further feature of my invention the relay is arranged so that in readiness for the next operation the contact actuating element, is returned to its initial position while disengaged from the motor. In a preferred manner of achieving this end the contact actuating element is arranged to be coupled with the motor through a free-Wheeling or one-way clutch device which allows the motor to rotate continuously independently of the contact actuating element but which when the contact actuating element is moved by the application thereto of the operating force becomes effective to couple the element with the motor so that the latter limits the speed of-an initiating force a Contact actuating element rof the former. With this arrangement, when the contact actuating element is returned to its initial position the free-wheeling or one-way clutch device, does not transmit the movement of the contact actuating element to the motor whereby the latter is allowed to rotate continuously.

My invention will be better understood from the following' description` when considered in connection with the accompanying drawing, and its scope will be pointed out in the appended claims.

In the accompanying drawing Fig. 1 illustrates in perspective, with certain parts shown partly broken away, a time element electroresponsive device such as a timing relay embodying my invention; and Fig. 2 illustrates in perspective a modication of a part of the embodiment of my invention shown in Fig. 1.

In the timing relay shown the various parts are supported from a pair of frame plates I and 2.

The operating force is provided by a solenoid 3 mounted on a tubular guide 4 which s suitably secured to the frame plate I. The solenoid cooperates with a plunger 5 working freely within the guide 4. This plunger carries a rack 6 which is adapted to mesh with a pinion I secured to a sleeve 8. This sleeve is freely mounted on a spindle 9 mounted between and journalled in the frame plates I and 2.

A constant speed motor such as a small synchronous motor I5 of any suitable type is mounted on the outer side of the frame plate I and is .coupled with the spindle 9 through a suitable train of gears such as a pinion II secured to the rotor shaft of the synchronous motor, a gear wheel I2 mounted on a counter-shaft I3 mounted between and journalled in the frame plates I and 2 and a pinion I4 also mounted on the counter-shaft and with a gear wheel I5 mounted on the spindle 9.

A hardened steel disc I6 is secured to the sleeve 8 and this disc is surrounded by a steel ring I1 secured to the gear wheel I5. The ring I1 is also axially registered with respect to the sleeve 8 and the spindle 9 by means of a cover plate I8 through which the sleeve freely extends.

The ring Il is provided on its inner surface with one or more tapered or curved recesses such as that shown at I9. There may be, for example, two such recesses disposed diametrically opposite one another. A steel ball is housed in each recess, so as to contact with the inner surface of the ring within the recess on the one hand and with the peripheral surface of the disc I6 on the other hand. The recesses I9 are tapered or curved in the manner shown and the arrangement constitutes a free wheeling device of the well known type in which the balls 20 are wedged in the recesses thereby to lock the disc I6 within the ring Il when the disc rotates in the appropriate direction but will allow free relative movement of said parts in the opposite direction, Small compression springs such as 2l may be provided for urging the balls towards the narrow end of the recesses.

At its upper end the solenoid carries an axial guide 22 in which is slidalbly located a pin 23. This pin projects as shown into the space within the guide 4. At its upper end the pin 23 engages with a spring leaf contact 24 which is secured at 25 to a terminal block 26 also mounted on the solenoid. This contact, which is the movable contact of the relay, cooperates with one or more stationary contacts mounted on the terminal block 2E. For example, in the arrangement shown there is a normally closed contact 2l and a normally open contact 28. It will be appreciated however that any desired number of contacts may be provided for connection in circuit according to the requirements of the equipment of which the timing relay is to form a part.

The guide 4 is provided below the solenoid with a longitudinal slot 29 through which extends a radial pin 3E carried by the plunger 5. As shown the guide is screw-threaded externally and an adjusting ring-nut 3l is mounted thereon, the upper face of this ring-nut cooperating with the pin 30 to determine the lowermost position of the plunger 5 and the rack 6 whereby to control the pick-up of the plunger'.

The plunger 5 is illustrated in the drawing in an intermediate position but as will be understood will normally occupy the lowermost position just above referred to.

In the operation of the timing relay the synchronous motor is energized so as to rotate continuously and to drive the gear wheel I5 in the direction indicated by the arrow thereon. Under these conditions the balls 25 release the ring I1 from the disc I6 so that the synchronous motor rotates freely while the plunger 5, the rack 6 and the disc I6 remain at rest. Upon energization of the solenoid the plunger will be` attracted upwardly and the rack 6 will drive the pinion l and the disc I6 in the direction of the arrow in the figure and the disc will become locked with the ring Il. In the illustrated embodiment of my invention this, of course, means that the plunger movement tends to rotate the disk I6 faster than the motor turns the ring Il. As a consequence the upward movement of the plunger under the action of the operating force provided by the solenoid is restrained by the synchronous motor and the plunger is allowed to move upwardly only at a speed determined by the synchronous speed of the motor. This will lbe obvious since the upward pull of the armature 5 is ineffective to accelerate the motor ID by reason of the speed changing mechanism bei tween the motor and the ring l1.

At the expiration of a sufficient time period the total angular movement of the motor will be such that the lower end of the rack 6 disengages itself from the pinion l. Thereafter the plunger will be attracted with rapidity and will strike the contact actuating element smartly to cause actuation of the relay contacts. The plunger will remain in its uppermost position and the relay contacts will remain operated as long as the solenoid is energized. Upon deenergization of the solenoid the plunger falls to the bottom of its stroke as limited [by the ring-nut 3|. During this return movement of the plunger the rack 6 drives the pinion l and disc I6 in the reverse direction since under these conditions the balls 20 are ineiective to transmit the rotation of the disc to the ring Il and the synchronous motor is permitted to `continue its constant speed rotation.

It will be seen that the time period provided by the timing relay above described will depend upon the movement which the plunger 5 must make before it disengages the rack 6 from the pinion l. Consequently by altering the axial position of the nut 3i on the guide 4 thereby to adjust the lowermost position of the plunger the time period may be adjusted as desired within the range provided by the relay.

The nut 3| Working on the screw-threaded lower part of the guide 4 has been shown as the adjusting means for the sake of clearness in the drawing but it will be understood that any other suitable means may be employed for limiting the lowermost' position of the plunger. Thus, in a preferred arrangement of the relay as devised for timing the operation of a spot welding machine such adjusting means as shown in Fig. 2 comprises Va cam 32 in the form of a disc mounted eccentrically upon a horizontal shaft 33, the peripheral edge of the disc cooperating with the pin 30 at its end remote from the guide 4. The horizontal shaft 33 carries a suitable setting member which may conveniently be in the form of a lever 34 provided with locking means 35 and cooperating with a scale provided on a casing 3B for the timing relay. In this example the timing relay provides a timing period adjustable over a range of from one-iiftieth of a second to four seconds and provides operation which is consistent to about one-hundredth part of a second. As will be appreciated any other desired range may be obtained by, suitable modification of the gear train for the synchronous motor.

While I have shown and described my invention in considerable detail, I do not desire to be limited to the exact arrangements shown, but

seek to cover in the appended claims all those modifications that fall within the true spirit and scope of my invention:

What I claim as new and desire to secure by Letters Patent of the United States is:

1. A time element electroresponsive device comprising an electromagnet having a movable armature and an energizing winding for actuating said armature in one direction, a constant speed motor having a continuously rotating element, a driving connection between said motor and said armature comprising a one-way clutch for retarding said armature against movement by said winding in said one direction through a predetermined range of angular movement of the rotating element of said motor.

2. A time element electroresponsive device comprising a motor having an element continuously rotating at a substantially constant speed, a movable operating member, means for actuating said member in one direction, means operative upon movement of said member in said one direction for establishing a one-way coupling between said member and the rotating element of said motor for retarding the movement of said member during a part of its movement in said one direction.

3. A time element electroresponsive device comprising a motor having an element continuously rotating at a substantially constant speed, a movable member, actuating means therefor, means operative in responsive to the initial movement of said member by said actuating means for mechanically coupling said member to the rotating element of said motor during a predetermined angular movement thereof, said member being subsequently free to move solely under the iniiuence of said actuating means.

l 4. A time element electroresponsive device comprising a motor having an element continuously rotating at a substantially constant speed, a movable member, actuating means therefor, means operative in response to the movement of said member from an initial position by said actuating means for mechanically coupling said member to the rotating element of said motor during a predetermined angular movement thereof, said member being subsequently free to move solely under the influence of said actuating means, and means for varying the initial position of said member whereby to change the operating time of the device.A

5. A time element relay comprising a motor having an element continuously rotating at substantially constant speed, relatively movable cooperating contacts, electromagnetic means for controlling said contacts comprising an armature and an energizing winding, means controlled by said armature for coupling said element and said armature following movement of the armature from an initial position by said winding and during a predetermined angular movement of said element while said winding remains energized, said coupling means being ineffective to delay the movementv of said armature at the end of said angular movement, and means for varying the initial position of said armature whereby to vary the time necessary to effect a circuit controlling action of said contacts.

6. A time element relay comprising a mo-tor having an element continuously rotating at substantially constant speed, electromagnetic means comprising an armature and an energizing winding, means controlled by said armature for coupling said element and said armature following movement of the armature from an initial position by said winding and during a predetermined angular movement of said element while said winding remains energized, said coupling means being ineffective to delay the movement of said armature at the `end of said angular movement.

'7. A time element relay comprising a motor having an element continuously rotating at a substantially constant speed, a first rotatable coupling member actuated in one direction by said motor, electromagnetic means comprising an armature and an energizing winding, a second rotatable coupling member actuated in said one direction by said armature upon movement thereof, means operative upon movement of said second coupling member in said one direction for preventing relative movement of said coupling members in said one direction, means for permitting a free movement of the armature after a predetermined joint movement of the two coupling members, and means for varying the point in the movement of the armature at which relative motion of the coupling members is prevented.

8. A time element relay comprising a motor having an element continuously rotating at a substantially constant speed, a rst rotatable coupling member actuated in one direction by said motor, electromagnetic means comprising an armature and an energizing winding, a second rotatable coupling member actuated in said one direction by said armature upon movement thereof, means operative upon movement of said second coupling member in said one direction for preventing relative movement of said coupling members in said one direction, and means for permitting a free movement of the armature after a predetermined joint movement of the two coupling members.

9. A time element relay comprising a motor having an element continuously rotating at a substantially constant speed, a first rotatable coupling member actuated in one direction by said motor, electromagnetic means comprising an armature and an energizing winding, a second rotatable coupling member actuated in said one -direction by said armature upon movement thereof, means operative upon movement of said second coupling member in said one direction for preventing relative movement of said coupling members in said one direction operative to permit movement of said second coupling member in the opposite direction independently of the movement of said first coupling member in said one direction.

10. A time element electroresponsive device comprising .an electromagnet having a movable armature and an energizing winding for actuating said armature from an initial position in a predetermined direction, a member continuously rotated at a predetermined constant speed and normally disconnected from said armature, and means responsive to the actuation of said armature from said initial position by said Winding for establishing a connection between the armature and the member during a predetermined movement of the armature in said direction whereby the actuation of said armature is dependent upon the speed of said member.

11. A time element electroresponsive device comprising an electromagnet having a movable armature and an energizing winding for actuating said armature in a predetermined direction, a member continuously rotated at a predetermined constant speed and normally disconnected from said armature, and means responsive to the actuation of said armature in said direction by said Winding for establishing a connection between said armature and said member whereby to control the actuation of said armature in said direction in accordance with the speed of said member.

i2. A time element electroresponsive device comprising an eleotromagnet having a movable armature and an energizing winding for actuating said armature from an initial position in a predetermined direction, a member continuously rotated at a predetermined constant speed and normally disconnected from said armature, means responsive to the initial actuation of said armature in said direction by said winding for establishing a connection between the armature and the member whereby to control the actuation of the armature in dependence on the speed of said member, and means for varying the initial position of said armature whereby to change the time of action of the device.

TREVOR LUNSDEN HERBERT BUTTERFIELD. 

